As Canadian governments turn increasingly to generic drugs to try to rein in health-care costs, some researchers suggest duplicates can sometimes differ significantly from the brand-name original, potentially causing serious trouble for patients.

One Montreal psychiatrist recently documented adverse effects in patients who were switched to generic medications, and alleged that the cost savings of generics are outweighed in certain cases by the dangerous impact on users.

“I’ve seen it enough times to know it’s a real phenomenon,” said Dr. Howard Margolese. “It’s sort of another element a physician has to consider if he has a patient who does well, and starts to relapse. ... There needs to be a little more caution and there needs to be a whole lot more study done before a generic is deemed to be equivalent.”

Other experts, Health Canada and the generic industry, however, say there is no reliable evidence that the copies are problematic, with some arguing that the skepticism is being fuelled by a brand-name sector worried about its bottom line.

They note the government requires that generic manufacturers prove their version delivers an equivalent amount of medication into patients’ bloodstream, and that brand-name companies must use the same tests when they change drug formulations internally.

“Brand-name manufacturers do fantastic research,” said Dion Brocks, a pharmaceutical science professor at the University of Alberta. “But unfortunately there is the business side of it, too. If you can delay a generic manufacturer getting their product on the shelves even one day (by questioning the quality of generics), that can mean tens of millions of dollars of sales.”

Health Canada hosted an expert panel discussion in June to decide if the standards for determining bioequivalence — whether two versions of a drug are essentially the same medicine — need to be tightened for certain types of drugs. The panel concluded the rules were strong enough.

“There are no differences as far as quality, purity, effectiveness and safety between generic drugs and higher-priced brand name drugs,” said Jeff Connell, spokesman for the Canadian Generic Pharmaceutical Association.

With some of the biggest-selling pharmaceuticals coming off patent, generic medications are grabbing an increasing share of the market, accounting for about 56% of prescriptions. Provincial governments, in turn, are trying to more aggressively take advantage of the competition, after years of criticism that Canadian generic prices were too high.

Earlier this year, the Ontario government slashed prices to 25% of the brand-name cost.

The assumption is that the generics are exact duplicates, with some health economists actually referring to them as a commodity product, like gold or oil, with no real difference from one maker to another.

In a paper published recently, however, Dr. Margolese, part of the clinical psychopharmacology unit at McGill University Health Centre, argued otherwise.

No one questions that generics contain the same medicine as the brands. He suggested the problems lie with excipients - the non-active ingredients - used by generic manufacturers and how they affect the release and absorption of drugs.

Dr. Margolese, who has received brand-name industry funding, cited three cases, involving patients with schizophrenia and major-depressive disorder. All went abruptly from being stable to feeling depressed and having suicidal thoughts. Investigation revealed the three had shortly before been switched to a generic version of an anti-depressant or anti-convulstant. All became healthy again after the branded drug was restored, he reported in the journal International Clinical Psychopharmacology.

But Mr. Connell noted that such individual case studies are weak evidence, and cited a 2005 Canadian trial, co-authored by a generic-company executive, that suggested psychology influences patients’ perceptions about generics, even when proven to be the same drug.

Dr. Pierre Blier, a Canada research chair in psychopharmacology at the Royal Ottawa Hospital, has long studied, though, what he considers significant differences between some generic and branded drugs. Problems have cropped up with transplant anti-rejection drugs, blood-pressure medication and blood thinners, among others, he said.

While generic companies must prove their drugs are bioequivalent to get approval, important variations can occur later between batches, charged Dr. Blier. He headed a 2009 study on 12 healthy subjects that compared versions of two popular anti-depressants. He concluded one generic was a good copy, but the other released its active ingredient too quickly and was not bioequivalent.

“In my view, it’s a very important health issue for our patients,” he said. “You do not need to have a whole lot of medications to be off to have a lot of problems.”

He acknowledged the study received a total of $40,000 in funding from four brand-name pharmaceutical companies, while the professor himself has financial ties to a number of firms, including some for whom he has worked as a contract employee.

Prof. Brocks said the Blier research was flawed in its methodology and, “given that the senior author is funded heavily by the trade-name industry, I would not place much on the outcome of this study.”

David Dubins, a pharmaceutical scientist at the University of Toronto who used to work in the generic industry, said he is confident that generics are faithful copies of the original, and writes off any controversy to “bickering” between companies.

tblackwell@nationalpost.com

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